Lens barrel and picture taking apparatus having the same

ABSTRACT

A lens barrel movable between a collapsed position and a photographing position, and a picture taking apparatus using the lens barrel. The lens barrel has lens groups movable along an optical axis, a deformable mirror supported in the lens barrel, the deformable mirror having a reflecting surface which varies to vary its optical power, a picture taking optical system including the lens groups and the deformable mirror, and a driving mechanism for retracting the deformable mirror from a light path of the picture taking optical system when the lens barrel lies at the collapsed position, and inserting the deformable mirror into the light path of the picture taking optical system when the lens barrel lies at the photographing position.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefits of Japanese Patent Application No.2002-31,425, filed on Feb. 7, 2002, in Japan, the contents of which arehereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of The Invention

The present invention relates to a lens barrel and an image captureapparatus such as a camera having the same.

2. Description of the Related Art

In recently popular, compact zoom cameras, a zoom lens barrel needs tomove in (collapse) and out (project) to cover its photographing rangefrom a wide angle state to a telephoto state. A so-called collapsibletype zoom lens barrel has also been put to practical use. Thecollapsible type zoom lens barrel is a zoom lens barrel which, when acamera need not perform photography, is collapsed into, and accommodatedwithin, the body of the camera to make the camera more compact so that auser can easily carry the camera. In addition, in recent years, therehave been increasing demands for higher (optical) zooming ratios, andhigher zooming ratios lead to a larger difference between the length ofa lens barrel in its wide angle state or its collapsed state and thelength of the lens barrel in its telephoto state. To cope with thisproblem, it has been necessary to provide a lens barrel structure whichcan be extended to a longer length, i.e., a multi-segmented zoom lensbarrel.

In addition, there are demands for further miniaturization of camerashaving such zoom lens barrels. In view of these demands, numerousproposals have heretofore been made. Examples of arts related to theinvention are a lens barrel described in Laid-Open Japanese PatentApplication No. Hei 11-258,678 and a collapsible lens mechanism for asingle-lens reflex camera described in Laid-Open Japanese PatentApplication No. Sho 55-52,038.

The proposal described in the above-recited Laid-Open Japanese PatentApplication No. Hei 11-258,678 is a camera including a lens barrel whichis made of a first lens group which is stationary at the front position,a plurality of movable lens groups disposed behind the first lens group,optical axis varying means disposed between the front end and the rearend of an optical system composed of the plurality of movable lensgroups for varying the direction of an photographing optical axis, anddriving means for moving each of the plurality of movable lens groupsthat are disposed before and behind the optical axis varying means, inthe direction of the photographing optical axis. This proposal, aims atminiaturizing the entire camera by reducing the diameter of the firstlens group lying at the front position (the front lens group).

The proposal described in Laid-Open Japanese Patent Application No. Sho55-52,038 is a collapsible lens mechanism for a single-lens reflexcamera which includes a mechanism for retracting a mirror from aphotographing optical axis in combination with the collapsing operationof a lens. This proposal aims to miniaturize the entire camera bycollapsing a photographing lens into a position from which the mirrorhas been retracted.

However, in the proposal described in the above-recited Laid-OpenJapanese Patent Application No. Hei 11-258,678, a reflecting mirrorwhich is the optical axis varying means is disposed before an aperturediaphragm, and a plurality of movable lens groups of a variablemagnification lens system which indispensably needs a certain degree ofmoving distance to perform a zooming operation is accommodated in thecamera body, so that it is extremely difficult to miniaturize the camerabody.

The proposed camera described in Laid-Open Japanese Patent ApplicationNo. Sho 55-52,038 is provided with a mechanism for retracting a mirrorfrom a photographing optical axis in combination with the collapsingoperation of a lens and which can collapse a photographing lens into avacant space from which the mirror has been retracted. This art has beenpracticed for the viewfinders of single-lens reflex cameras, but is notintended to be applied to picture taking optical systems.

Further, according to the art disclosed in Japanese Patent Laid-Open No.Hei 7-27,963, a zoom lens barrel has a three-step shifting mechanism.More specifically, it has a stationary tube on its outermostcircumference, and has a structure which moves an inside frame from acollapsed position to a photography-enabled projected position by meansof gears inside the stationary tube. It performs zooming from a wideangle end position to a telephoto end position.

The art disclosed in Japanese Patent Laid-Open No. Hei 8-313,788 has astructure which performs shifting from a collapsed position to aphotography-enabled projected position by means of a lead screw and,after that, performs zooming by rotating an outer circumferentialrotating frame.

The lens barrel disclosed in Japanese Patent Laid-Open No. Hei 11-72,682can be driven to switchably perform a set-up shifting movement from alens-barrel collapsed position to a photography-enabled projectedposition and a shifting movement within a zooming range. This lensbarrel includes a set-up gear for shifting the above-described barrelframe from the collapsed position to the projected position, and azooming gear for turning the barrel frame at the projected position toperform driving for zooming. The set-up gear and the zooming gear aresupported on a stationary frame. Each of the set-up gear and the zoominggear uses an axially long gear which extends into a movement zone fromthe collapsed position to the projected position.

SUMMARY OF THE INVENTION

The invention aims to reduce the size of a picture taking apparatus suchas a camera having a reflecting mirror in its photographing light path.

In accordance with one aspect of the invention, a picture takingapparatus comprises a lens barrel movable between a collapsed statewhere the lens barrel is accommodated in a body of the apparatus and aphotographing state where the lens barrel is projects from the body ofthe apparatus, a picture taking optical system, a refracting mechanismfor retracting the deformable mirror from a light path of the picturetaking optical system when the lens barrel is in the collapsed state,and inserting the deformable mirror into the light path of the picturetaking optical system when the lens barrel is in the photographingstate, and a control part for varying a reflecting surface shape of thedeformable mirror to vary optical power thereof. The picture takingoptical system includes a lens group driven to move along an opticalaxis by the lens barrel and a deformable mirror supported in the lensbarrel.

In accordance with another aspect of the invention, a lens barrelcomprises an optical system including at least one lens and a reflectingmember for reflecting light passing through the at least one lens, animage pickup element provided at a position where the image pickupelement can receive light reflected from the reflecting member, and aframe which supports the reflecting member and the image pickup element.The reflecting member is supported on the frame in such a manner as tobe insertable into and retractable from a light path of the opticalsystem.

In accordance with still another aspect of the invention, an imagecapture apparatus comprises a lens system including a plurality of lensgroups adapted to move along an optical axis which defines at least apart of an image acquiring optical path, and a mirror. The lens systemhas a first state and a second state, and when the lens system is in thefirst state, the mirror is positioned in the image acquiring opticalpath in a defined space, and when the lens system is in the secondstate, each of at least two of the plurality of lens groups occupy atleast a part of the defined space.

In accordance with still another aspect of the invention, an imagecapture apparatus having an image acquiring optical path, comprises amirror and a mirror retracting part. The mirror has a first state inwhich it is positioned in the image acquiring optical path, and a secondstate in which it is positioned outside the image acquiring opticalpath. The mirror and mirror retracting part are substantially parallelwith respect to each other when the mirror is in the second state.

The other aspects of the invention will become apparent from thefollowing description of examples and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention will become more fully understood from the detaileddescription given-below and the accompanying drawings, which are givenby way of illustration only and thus are not limitative of thisinvention, wherein:

FIG. 1 is a perspective view of one example of a camera according to theinvention, showing an external appearance of the camera as viewed fromthe front side thereof;

FIG. 2 is a block diagram showing portions of an electrical circuit ofthe camera;

FIG. 3 is a view showing a deformable mirror fitted in the camera andelements for driving the deformable mirror;

FIG. 4 is an explanatory view showing one example of the electrodes usedwith the deformable mirror;

FIG. 5 is an explanatory view showing another example of the electrodesused with the deformable mirror;

FIG. 6 is an exploded perspective view of a lens barrel capable ofzooming;

FIG. 7 is an explanatory cross-sectional view of the construction of thelens barrel which varies during zooming;

FIG. 8 is a developed view of the inner circumferential surface of thestationary frame shown in FIG. 7;

FIGS. 9A-9C are explanatory views of shifting movement which occursduring the zooming of the lens barrel;

FIG. 10 is a cross-sectional view of the essential portions of the lensbarrel placed at a wide angle end;

FIG. 11 is a cross-sectional view of the essential portions of the lensbarrel placed at a collapsed position; and

FIG. 12 is a flowchart showing an example of the photographing operationcontrol of a CPU incorporated in the camera.

FIG. 13 is a view showing an A-A cross section of the stationary framein FIG. 8.

DETAILED DESCRIPTION OF THE EXAMPLES OF THE INVENTION

FIGS. 1 to 13 are views showing examples of a camera according to thisinvention.

FIG. 1 is a perspective view of the external appearance of the camera asviewed from the front side thereof, and FIG. 2 is a block diagramshowing the essential portions of an electrical circuit of the camera.

The body and the constituent elements of a camera 1 is covered with anexterior member which is mainly formed by a front cover 1 a and a backcover 1 b which constitute a camera body 2, and a barrier 1 c disposedfor sliding movement in opposite directions along the front surface ofthe front cover 1 a, i.e., in opposite directions perpendicular to theoptical axis of a picture taking optical system 5 a (which will bedescribed later).

Various kinds of control members are arranged on exterior surfaces ofthe exterior member of the camera 1, and various kinds of constituentelements disposed inside the camera 1 are arranged at predeterminedpositions in such a manner as to be partly exposed to the outside.Control members such as a release button 8 and a plurality of modeswitching buttons 9 and a display panel 10 are disposed on the topsurface of the camera 1. The release button 8 is a control member to bemanipulated by a user when the user is to start a photographingoperation. The plurality of mode switching buttons 9 are control membersfor performing various setting manipulations such as the setting ofphotographing operation modes, the setting of an internal clock and thesetting of the function of an electronic flash. The display panel 10 ismade of a liquid crystal display device (abbreviated as LCD) or thelike, and visually perceptibly displays photographing mode information,date information, state information as to the camera 1 and otherinformation in a predetermined form such as pictures and characters.

An electronic flash window 7 is arranged at a predetermined positionnear the top periphery of the front surface of the camera 1 on one sidethereof. The electronic flash window 7 protects the front surface of anelectronic flash light source 23 (refer to FIG. 2), and irradiates apredetermined area including an object lying on the front side of thecamera 1, with a flash of light emitted from the electronic flash lightsource 23.

The picture taking optical system 5 a is arranged approximately in thecenter of the front surface of the camera 1 in the state of being heldby a lens barrel 5 b. The picture taking optical system 5 a forms anobject image on a light-sensitive surface of an image pickup device 13(refer to FIG. 2) via a deformable mirror 40 arranged in the interior ofthe camera 1.

A viewfinder window 6 is disposed at the periphery of the picture takingoptical system 5 a and in the vicinity of the top periphery of theexterior member of the camera 1. This viewfinder window 6 is disposed tocover the front surface of the objective lens of a viewfinder opticalsystem.

A zoom lever ZL or the like to be manipulated by the user when the useris to cause the picture taking optical system 5 a to perform a zoomingoperation is disposed at a position near the top periphery of the backsurface of the camera 1 on the opposite side thereof. The barrier 1 c isdisposed for sliding movement with respect to the front cover 1 a in theopposite directions indicated by an arrow X in FIG. 1. This barrier 1 cis arranged so that when the user is to perform photography with thecamera 1, the user slides the barrier 1 c to the left as shown in FIG.1, whereby the barrier 1 c can turn on the power source of the camera 1in combination with a power source switch (not shown) inside the camera1. When the user is to stop photography and carry or keep the camera 1,the user slides the barrier 1 c to the right as shown in FIG. 1, wherebythe barrier 1 c can initiate retracting the lens barrel and turn off thepower source of the camera 1 similarly in combination with the powersource switch, and covers and protects constituent parts such as thepicture taking optical system 5 a, the lens barrel 5 b and theviewfinder window 6 disposed on the front surface of the camera 1. Inaddition, when the barrier 1 c is opened from a closed position, thelens barrel 5 b which is in a collapsed state is set up at a wide angleend position in which the focal length of the picture taking opticalsystem 5 a is shortest. Incidentally, the state shown in FIG. 1represents the state in which the barrier 1 c is in an open state andthe lens barrel 5 b is still collapsed.

The construction of the electrical circuit incorporated in the camera 1will be described below in detail with reference to FIG. 2.

As shown in FIG. 2, the camera 1 mainly includes a control circuit 11,the picture taking optical system 5 a containing a variablemagnification lens system 12 and the deformable mirror 40, the imagepickup device 13, an image signal processing circuit 14, a lens positiondetecting circuit 15, a motor driving circuit 16, driving motors 17 and20, an aperture diaphragm 18, a shutter control circuit 19, a sectorposition detecting circuit 21, an electronic flash control circuit 22,the electronic flash light source 23, an operation mode setting circuit24, a display control circuit 25, a mirror driving circuit 26, a displaypart 27 such as an LCD, first and second release detecting switches 8 aand 8 b each of which detects a state of the release button 8, the modeswitching buttons 9 and the display panel 10. In this example, thedisplay part 27 is disposed on the back surface of the camera 1, and isnot shown in FIG. 1.

The control circuit 11 is made of, for example, a CPU, and is controlmeans for controlling various kinds of operations of the entire camera1.

In the camera 1, the picture taking optical system 5 a includes thevariable magnification lens system 12, the aperture diaphragm 18 and thedeformable mirror 40. The variable magnification lens system 12 is madeof first, second and third lens groups 30, 31 and 32 and is driven inthe direction of its optical axis by the lens barrel 5 b (refer toFIG. 1) which can move between a collapsed position at which the lensbarrel 5 b is accommodated in the camera body 2 and a photographingposition at which the lens barrel 5 b extends from the camera body 2.The aperture diaphragm 18 is disposed between the second lens group 31and the third lens group 32. The deformable mirror 40 is supported to beinsertable into and retractable from the light path of these lens groups30, 31 and 32, and is disposed at the rear stage of the aperturediaphragm 18. A more detailed description of the construction ofexemplary deformable mirrors will be given later.

Light from an object which has passed through the first, second andthird lens groups 30, 31 and 32 is reflected by the deformable mirror 40and is made incident on the light-sensitive surface of the image pickupdevice 13, thereby forming an object image on the image pickup device13. The image pickup device 13 converts the formed object image into ananalog image signal, and supplies the analog image signal to the imagesignal processing circuit 14.

The image signal processing circuit 14 applies digitizing processing tothe supplied analog image signal, performs the signal processing todisplay the digital image signal on the display part 27 including theLCD, as well as various kinds of processing to perform contrastdetection type auto-focus, and supplies the obtained picked-up imagedata to the CPU 11. Typically, to conserve the battery of the camera,image data is not displayed on the LCD until the user manipulates thecamera. When the user manipulates the camera, the CPU 11 supplies to thedisplay control circuit 25 the picked-up image data containing the imagesignal supplied from the image signal processing circuit 14. At the sametime, the CPU 11 performs control on the display control circuit 25 sothat an image based on the picked-up image data is displayed on thedisplay part 27 such as an LCD provided on, for example, the backsurface of the camera body 2. Namely, the display part 27 displaysinformation such as the date, of photography and the f-number and theshutter speed used for photography, together with the picked-up imagesignal. In addition, the CPU 11, on the basis of the supplied picked-upimage data (contrast data), controls the shape of the reflecting surfaceof the deformable mirror 40 so that contrast reaches a peak.

The lens position detecting circuit 15 detects the state of movement ofeach of the lens groups 30, 31 and 32 in the variable magnification lenssystem 12, respectively, during, for example, a zooming operation, andoutputs the detection result to the CPU 11. When the CPU 11 receives thedetection result, the CPU 11 controls on the motor driving circuit 16 onthe basis of the detection result from the lens position detectingcircuit 15. The rotational driving force of the driving motor 17 istransmitted to a lens barrel driving mechanism which is not shown,whereby each of the lens groups 30, 31 and 32 can be moved to a zoomingposition according to inputs commanded from the user.

The aperture diaphragm 18 is arranged between the second lens group 31and the third lens group 32 in the picture taking optical system 5 a.The aperture diaphragm 18 is operated by the motor 20 via a shutterdriving mechanism which is not shown, and the motor is controlled by theshutter control circuit 19. For example, when the aperture diaphragm 18is brought to an open state, an object image is formed on the imagepickup device 13. The sector position detecting circuit 21 detects thestate of opening or closure of the aperture diaphragm 18, and outputsthe detection result to the CPU 11. When the CPU 11 receives thedetection result, the CPU 11 instructs and controls the shutter controlcircuit 19 on the basis of the detection result from the sector positiondetecting circuit 21, thereby controlling the opening/closing operation,the shutter speed and the like of the aperture diaphragm 18.

The electronic flash control circuit 22 is a circuit which is, at thetime of the execution of an electronic flash photography mode, chargedwith the voltage required to cause the electronic flash light source 23to emit a flash of light and applies this charged voltage to theelectronic flash light source 23 to cause it to emit a flash of light.The operation of the electronic flash control circuit 22 is controlledby the CPU 11.

The release button 8 of a two-stroke type is adopted in the camera 1. Asshown in FIG. 2, the release button 8 is provided with the first releasedetecting switch 8 a and the second release detecting switch 8 b. Theserelease detecting switches 8 a and 8 b are switches which operate incombination with the release button 8, and when the release button 8 isdepressed to a first stroke position, the first release detecting switch8 a is turned-on, and subsequently, when the release button 8 is furtherdepressed to a second stroke position, the second release detectingswitch 8 b is turned on. A switch manipulation signal from each of therelease detecting switches 8 a and 8 b is supplied to the CPU 11.

When the CPU 11 recognizes from the supplied switch manipulation signalthat the first release detecting switch 8 a has been turned on, the CPU11 performs control to execute AF (auto-focusing) and photometricmeasurement operations. Further, when the CPU 11 recognizes that thesecond release detecting switch 8 b has been turned on, the CPU 11performs control to execute a photographing operation. The photographingoperation is executed on the basis of a photographing mode set by theoperation mode setting circuit 24 via the mode switching buttons 9.

In the camera 1, as shown in FIG. 2, the deformable mirror 40, having anelectrically variable surface shape and therefore variable opticalcharacteristics, is provided in the light path of the picture takingoptical system 5 a. The camera 1 is provided with the deformable mirror40 having the optical function of reflecting light supplied from thevariable magnification lens system 12 onto the image pickup device 13disposed on a side portion of a stationary frame 50 (refer to FIG. 6) inthe lens barrel 5 b. Accordingly, it is possible to minimize the camerabody 2 by means of a simple construction. In addition, it is possible toexecute the focusing of the picture taking optical system 5 a without amechanical driving mechanism by varying the shape of the reflectingsurface of the deformable mirror 40.

More specifically, the deformable mirror 40 is secured to the inside ofthe stationary frame 50 (refer to FIG. 6) of the lens barrel 5 b via alink mechanism 60 (refer to FIG. 10), and is supported to be insertableinto and retractable from the light path of the first, second and thirdlens groups 30, 31 and 32. When the lens barrel 5 b is placed at thecollapsed position, the link mechanism 60 retracts the deformable mirror40 from the light path of the first, second and third lens groups 30, 31and 32. When the lens barrel 5 b is placed at the photographing positionso that the camera 1 can perform a photographing operation, the linkmechanism 60 inserts the deformable mirror 40 into the light path of thefirst, second and third lens groups 30, 31 and 32. Construction detailsof an exemplary link mechanism 60 will be described later.

The deformable mirror 40 is made of a reflecting surface 40 a andelectrodes 40 b for controlling the shape of the reflecting surface 40a, and the electrodes 40 b are driven by the voltage supplied from themirror driving circuit 26. Namely, the CPU 11 performs driving controlon the mirror driving circuit 26, thereby varying the shape of thereflecting surface of the deformable mirror 40 based on the status ofphotography.

Exemplary deformable mirrors 40 will be described below in greaterdetail with reference to FIGS. 3 to 5.

FIG. 3 is a view showing the deformable mirror 40 fitted in the camera 1and elements for driving the deformable mirror 40, FIG. 4 is a viewshowing one example of the electrodes 40 b used with the deformablemirror 40, and FIG. 5 is a view showing another example of theelectrodes 40 b used with the deformable mirror 40.

As shown in FIG. 3, the deformable mirror 40 is made of the plurality ofelectrodes 40 b and a thin film 40 a formed as the reflecting surface byaluminum coating. By varying the shape of the reflecting surface 40 a,optical characteristics of the mirror can be varied.

A plurality of variable resistors 41 are electrically connected to theplurality of electrodes 40 b, respectively, and the variable resistors41 are constructed so that their resistance values can be variablycontrolled when the CPU 11 performs driving control on the mirrordriving circuit 26. Namely, the driver 26 serves as a driving circuitfor possibly independently, controlling the resistance values of theplurality of variable resistors 41.

The other electrodes of these variable resistors 41 are connected to thenegative pole of a power source 42, and the positive pole of the powersource 42 is connected to another variable resistor 41 a. The otherelectrode of the variable resistor 41 a is connected to a power sourceswitch 43, and the other end of the power source switch 43 is connectedto the thin film 40 a of the deformable mirror 40. The plurality ofvariable resistors 41, the power source 42, the variable resistor 41 aand the power source switch 43, all of which are electrically connected,are arranged between the thin film 40 a and the electrodes 40 b.

The thin film 40 a is, for example, a membrane mirror of the typedescribed in P. Rai-choudhury, Handbook of Microlithography,Micromachining and Microfabrication, Volume 2: Micromachining andMicrofabrication, p. 495, FIG. 8.58, SPIE PRESS or of the type describedin Optics Communication, Volume 140 (1997), pp. 187-190. Namely, whenvoltage is applied across the thin film 40 a and the plurality ofelectrodes 40 b, the thin film 40 a is deformed by electrostatic forceso that the surface shape of the thin film 40 a is varied and theoptical power of the reflecting surface is varied, whereby focusing canbe effected.

Incidentally, it is also possible to set the amount of deformationand/or the mode of variation of the surface shape in order to compensatefor a degradation in image-forming performance caused by the deformationof or variations in the refractive indices of the other lens groups dueto variations in temperature or humidity, the expansion or shrinkage ofa lens supporting frame, and the assembly error of parts such as opticalelements and frames. In addition, both focusing and correction ofaberration due to focusing can also be effected by the deformablemirror.

The shapes of the electrodes 40 b may be selected according to thedesired manner of deformation of the thin film 40 a, as shown in FIGS. 4and 5 by way of example. In addition, the deformable mirror 40 of highprecision can be obtained by using lithography to fabricate it.

The CPU 11 varies the resistance value of each of the variable resistors41, thereby controlling the shape of the thin film 40 a to optimize theimage-forming performance of the picture taking optical system 5 a.Namely, the signal outputted from the image signal processing circuit 14is inputted to the CPU 11. Then, on the basis of this input signal, theCPU 11 outputs a signal for determining the resistance values of therespective variable resistors 41 that are appropriate for compensatingfor a degradation in the image-forming performance which depends on thedistance to an object. Voltages to be applied to the respectiveelectrodes 40 b are determined by those resistance values. Since thethin film 40 a is deformed by the voltages applied to the respectiveelectrodes 40 b, i.e., electrostatic force, the shape of the thin film40 a is optimized. The thin film 40 a can assume various shapesincluding the shape of an aspherical surface.

In the case of this example; focusing can be executed at least in part,by varying the shape of the deformable mirror 40. An image is consideredto be in focus when the high-frequency component of an image signalsupplied from the image pickup device 13 reaches its maximum.

In addition, it is convenient to fabricate the thin film 40 a with asynthetic resin such as polyimide, because large deformation of suchthin films can be caused even by low voltages.

The construction and the operation of the lens barrel 5 b in which thedeformable mirror 40 is fitted will be described below in detail withreference to FIGS. 6 to 9C.

FIG. 6 is an exploded perspective view of the whole of the lens barrel 5b capable of zooming, and FIG. 7 is an explanatory view of theconstruction of the lens barrel 5 b which varies during zooming. FIGS.7(a) and 7(b) respectively show the collapsed state and the wide anglestate of the lens barrel 5 b. FIG. 8 is a developed view of the innercircumferential surface of the stationary frame 50 shown in FIG. 7, andFIGS. 9A-9C are explanatory views of lateral lens movement which occursduring the zooming of the lens barrel 5 b. In the following description,it is assumed that the object side of the lens barrel 5 b is the frontside and the image side of the lens barrel 5 b is the rear side. Inaddition, directions parallel to the optical axis of a zoom lens whichis made of the first lens group 30, the second lens group 31 and thethird lens group 32 are called an S0 directions, and the directions ofrotation about the optical axis are represented by rotational directionsas viewed from the object side.

As shown in FIGS. 6 and 7, the lens barrel 5 b includes the stationaryframe 50 which is fixedly supported on the camera body 2 and in whichthe deformable mirror 40 is incorporated, a cam frame 51 which is fittedin the stationary frame 50 for rotation about the optical axis and formovement in the S0 directions, a zooming frame (also called a first lensgroup supporting frame) 52 which is fitted in the cam frame 51 forturning movement about the optical axis with respect to the cam frame 51and for movement back and forth integrally with the cam frame 51 in theS0 directions, a second lens group supporting frame 53 which is fittedin the zooming frame 52 for movement in the S0 directions, a third lensgroup supporting frame 54 which is fitted in the zooming frame 52 formovement in the S0 directions, the deformable mirror 40 which is fittedfor turning movement in a mirror holding part 50 a of the stationaryframe 50, the aperture diaphragm 18 which, although not shown in eitherof FIGS. 6 or 7, is arranged in the zooming frame 52 and disposedbetween the second lens group supporting frame 53 and the third lensgroup supporting frame 54, and a driving gear 100 which is disposed inthe stationary frame 50 to transmit a driving force from a zooming unit(not shown) to the cam frame 51.

Further, the lens barrel 5 b has, as the picture taking zoom lensoptical system 5 a, the first lens group 30 supported on the zoomingframe 52, the second lens group 31 supported on the second lens groupsupporting frame 53, and the third lens group 32 supported on the thirdlens group supporting frame 54.

The stationary frame 50 is a ring-shaped member having openings at itsfront end (the object side) and at its rear end (the image side),respectively, and has a female helicoid part 50A provided on the innercircumferential part of the stationary frame 50 and made of femalehelicoid gears 50 e for restricting a set-up position and a plurality offemale helicoid gears 50 f formed on the inner circumferential part,linear guide grooves 50 g (refer to FIG. 7) which are groovesrespectively arranged at circumferentially different positions andformed to extend in the direction of the optical axis in concave shapesin cross section, a gear chamber 50 b formed to extend in the directionof the optical axis in a concave shape in cross section, the mirrorholding part 50 a which is formed in such a manner that the outercircumferential part of the stationary frame 50 is partly projected andwhich is arranged to turnably support the deformable mirror 40 at apredetermined position inside the mirror holding part 50 a, and a CCDholding part 50 c disposed in opposition to the mirror holding part 50 aand formed so that an image pickup member such as the image pickupdevice 13 is fixed inside the CCD holding part 50 c.

A specific construction of the deformable mirror 40 is shown in FIG. 6.A mirror holding frame 40 c is fitted to the mirror holding part 50 a ofthe stationary frame 50 by the link mechanism 60 which will be describedlater, and accommodates a deformable mirror body. The deformable mirrorbody is held by being fixed to a holding part 40 d formed in a concaveshape in the mirror holding frame 40 c. A flexible printed circuit boardinserting hole 40 e for leading a flexible printed circuit board (notshown) electrically connected to the deformable mirror 40 to the backside of the deformable mirror 40 is formed in the holding part 40 d.Bearing parts 40 f each having a hole 40 g through which to insert amirror turning shaft 40 h are formed on the proximal side of the mirrorholding frame 40 c. The mirror turning shaft 40 h (the middle portion ofwhich is cut away for simplicity) is pivotally supported in the mirrorholding part 50 a of the stationary frame 50. An urging spring 40 i isengaged with the mirror holding part 50 a of the stationary frame 50 andthe bearing parts 40 f, and normally urges the mirror holding frame 40 ctoward the interior of the stationary frame 50 (in the direction of theoptical axis).

A structure for securing the deformable mirror 40 and the image pickupdevice 13 to the stationary frame 50 will be described later.

The cam frame 51 is a ring-shaped member having openings at its frontand rear ends, respectively, and a male helicoid part 51A is formed onthe outer circumferential part of the cam frame 51 at the rear (imageside) end thereof. The male helicoid part 51A is made of male helicoidgears 51 a for restricting a set-up position, which are respectivelyformed at three positions to have predetermined widths in the directionof the optical axis, male helicoid gears 51 b arranged at a plurality ofcircumferential positions and formed to be smaller in width than themale helicoid gears 51 a for restricting a set-up position, and a gearpart 51 c disposed at a position where the male helicoid gears 51 b aredisposed.

The inner circumferential part of the cam frame 51 is provided withthree second lens group guiding cam grooves 51 d and three third lensgroup guiding cam grooves 51 e which extend in the same direction as, orwithout crossing, the second lens group guiding cam grooves 51 d.

When the lens barrel 5 b is in an assembled state, the male helicoidpart 51A of the cam frame 51 meshes with the female helicoid part 50A ofthe stationary frame 50, and the cam frame 51 is allowed to move backand forth in the S0 directions of the optical axis while turning withrespect to the stationary frame 50. The driving gear 100 which is formedof a spur gear which is axially long is rotatably inserted in the gearchamber 50 b of the stationary frame 50 in parallel with the opticalaxis. The driving gear 100 normally meshes with the gear part 51 c ofthe cam frame 51 and transmits rotating force to the cam frame 51.

The zooming frame 52 is a ring-shaped member having an openings at itsrear end and a lens holding part (not shown) for holding the first lensgroup 30, at its front end. Second and third lens group guiding lineargrooves 52 d are provided in the outer circumferential part of thezooming frame 52.

Further, the outer circumferential part of the rear end of the zoomingframe 52 is provided with three linear guide parts 52 a which extendradially outwardly, bayonet claws 52 b respectively arranged near thelinear guide parts 52 a, and a pressing part 52 c which comes intocontact with the link mechanism 60 to turn the deformable mirror 40.

When the lens barrel 5 b is in an assembled state, the zooming frame 52is fitted in the cam frame 51 with the respective linear guide parts 52a engaged with the linear guide grooves 50 g (refer to FIG. 7) of thestationary frame 50. In this case, the zooming frame 52 isbayonet-mounted to the inner circumferential surface of the cam frame 51by, the bayonet claws 52 b. Accordingly, since the rotation of thezooming frame 52 is restricted, the zooming frame 52 moves back andforth in the direction of the optical axis according to the rotation ofthe cam frame 51 without rotating in itself.

The second lens group supporting frame 53 is an approximatelyring-shaped frame member having a central opening, and three second lensgroup guiding pins 53 a are fixed to the rear end of the outercircumferential surface of the second lens group supporting frame 53.The second lens group 31 is held in the central opening. The third lensgroup supporting frame 54 is a ring-shaped frame member having a centralopening and holding the third lens group 32 in this central opening, andthree third lens group guiding pins 54 a are fixed to the outercircumferential surface of the third lens group supporting frame 54 inthe vicinity of this central opening.

When the lens barrel 5 b is in an assembled state, the second lens groupsupporting frame 53 is fitted in the zooming frame 52 for slidingmovement in the direction of the optical axis with the three second lensgroup guiding pins 53 a of the outer circumferential part of the secondlens group supporting frame 53 brought in engagement with the second andthird lens group guiding linear grooves 52 d of the zooming frame 52,respectively. Accordingly, the second lens group supporting frame 53 isguided in the S0 directions by the second and third lens group guidinglinear grooves 52 d of the zooming frame 52 and is driven in thedirection of the optical axis by the second lens group guiding camgrooves 51 d of the cam frame 51. The third lens group supporting frame54 is fitted in the zooming frame 52 for sliding movement in thedirection of the optical axis with the three third lens group guidingpins 54 a of the outer circumferential part of the third lens groupsupporting frame 54 brought in engagement with the second and third lensgroup guiding linear grooves 52 d of the zooming frame 52, respectively.Accordingly, the third lens group supporting frame 54 is guided in theS0 directions by the second and third lens group guiding linear grooves52 d of the zooming frame 52 and is driven back and forth in thedirection of the optical axis by the three third lens group guiding camgrooves 51 d of the cam frame 51.

The forward and backward movements during zooming of the lens barrel 5 bhaving the above-described construction will be described below indetail with reference to FIGS. 7 to 9C.

As shown in the partial cross-sectional view of FIG. 7(a), when the lensbarrel 5 b is in the collapsed state, all the frames are accommodated inthe interior of the stationary frame 50. During this time, the set-upposition restricting male helicoid gears 51 a of the cam frame 51 arerespectively arranged at collapsed positions L1 of the set-up positionrestricting female helocoid gears 50 a of the stationary frame 50engaged therewith as shown in FIG. 8.

When the lens barrel 5 b is to be shifted from the collapsed state tothe photography-enabled wide angle state shown in the cross-sectionalview of FIG. 7(b), the driving gear 100 is rotated counterclockwise by apredetermined amount via the zooming unit (driving mechanism) which isnot shown. Then, the cam frame 51 is shifted while being rotated by therotation of the driving gear 100. During this time, the cam frame 51linearly moves relatively forwardly together with the zooming frame 52guided linearly in an S0 direction.

The second lens group supporting frame 53 is shifted to the wide angleend position by the cam frame 51 while being guided linearly in the S0direction with the second lens group guiding pins 53 a engaging with thesecond and third lens group guiding linear grooves 52 d of the zoomingframe 52. Namely, the second lens group guiding pins 53 a move along thesecond lens group guiding cam grooves 51 d of the cam frame 51 which isrotating, whereby the second lens group supporting frame 53 is shiftedto the wide angle end position.

The third lens group supporting frame 54 is shifted to the wide angleend position by the cam frame 51 while being guided linearly in the S0direction with the third lens group guiding pins 54 a engaging with thesecond and third lens group guiding linear grooves 52 d of the zoomingframe 52. Namely, the third lens group guiding pins 54 a move along thethird lens group guiding cam grooves 51 e of the cam frame 51 which isrotating, whereby the third lens group supporting frame 54 is shifted tothe wide angle end position.

At this time, as shown in FIG. 8, the set-up position restricting malehelicoid gears 51 a of the cam frame 51 disengage from the set-upposition restricting female helicoid gears 50 e of the stationary frame50 and come respectively to wide angle positions L2 in a set-up positionrestricting groove 50 h formed to extend in the circumferentialdirection at an end portion of the stationary frame 50.

When the lens barrel 5 b is to be shifted from the wide angle state tothe telephoto state shown in FIGS. 9B-9C, the driving gear 100 isrotated further counterclockwise by a predetermined amount. Then, as thecam frame 51 is rotated by the rotation of the driving gear 100, thesecond lens group guiding pins 53 a move along the second lens groupguiding cam grooves 51 d of the cam frame 51 which is rotating, wherebythe second lens group supporting frame 53 is moved to a telephoto endposition (refer to FIG. 9C). At the same time, as the third lens groupguiding pins 54 a move along the third lens group guiding cam grooves 51e of the cam frame 51 which is rotating, the third lens group supportingframe 54 is also shifted to the telephoto end position (refer to FIG.9C). At this time, also as shown in FIG. 8, the set-up positionrestricting male helicoid gears 51 a of the cam frame 51 comerespectively to telephoto end positions L3 in the set-up positionrestricting groove 50 h of the stationary frame 50.

On the other hand, when the lens barrel 5 b is to be shifted into thecollapsed state, the driving gear 100 is rotated clockwise via thezooming unit (driving mechanism) which is not shown. The cam frame 51and the zooming frame 52 are relatively shifted by the rotation of thedriving gear 100, and the second lens group supporting frame 53 and thethird lens group supporting frame 54 are also relatively shifted to thecollapsed position by the reverse rotation of the cam frame 51.

The relative amounts of movements of the first to third lens groups 30to 32 during a zooming operation is shown in FIGS. 9A-9C. This movementrelationship similarly applies to the relationship between the zoomingframe 52 provided with the first lens group 30, the second lens groupsupporting frame 53 and the third lens group supporting frame 54.Namely, when the lens barrel 5 b is collapsed, the first to third lensgroups 30 to 32 are accommodated in the stationary frame 50 in the stateof being spaced apart from one another at predetermined intervals asshown in FIG. 9A. When the lens barrel 5 b is to be shifted from thecollapsed state to the wide angle end state, the first lens group 30,the second lens group 31 and the third lens group 32 are relativelyshifted so that the distance between the first lens group 30 and thethird lens group 32 increases with the distance between the first lensgroup 30 and the second lens group 31 remaining unchanged to maintainthe predetermined interval, as shown in FIG. 9B. After that, when thelens barrel 5 b is to be shifted from the wide angle end position to thetelephoto end position, the second lens group 31 and the third lensgroup 32 are respectively moved so that the distance between the secondlens group 31 and the third lens group 32 decreases with the position ofthe first lens group 30 remaining unchanged, as shown in FIG. 9C.

Further, the positioning of the cam frame 51 in the lens barrel 5 b ofthis example in the direction of the optical axis will be describedbelow in detail with reference to FIG. 13 as well. In FIG. 13, thestationary frame 50 is referred to as a first frame, and the cam frame51 is referred to as a second frame.

FIG. 13 is a view showing an A-A cross section in FIG. 8, and is across-sectional view showing a portion of a position restricting groovefor a second frame. Incidentally, in FIG. 13, one of the male helicoidgears 51 a of the cam frame 51, which lies at a position L2, is shown bya dot-dot-dashed line.

As shown in FIG. 13, the set-up position restricting male helicoid gears51 a provided on the outer circumference of the cam frame 51 (the secondframe) are larger in thread height and wider in thread width than themale helicoid gears 51 b provided at a plurality of positions. And, asshown in FIG. 8, the thread width of the set-up position restrictingmale helicoid gears 51 a is wider than the root width of the femalehelicoid gears 50 f.

The stationary frame 50 (the first frame) is provided with the set-upposition restricting female helicoid gears 50 e and the female helicoidgears 50 f at locations corresponding to the set-up position restrictingmale helicoid gears 51 a and the male helicoid gears 51 b, respectively.The root width of each of the set-up position restricting femalehelicoid gears 50 e, which are to accommodate male helicoid gears 51 a,is larger than the root width of each of the female helicoid gears 50 f,which are to accommodate male helicoid gears 51 b.

Position restricting projection guide portions 50 j are threads whichform the set-up position restricting female helicoid gears 50 e, andextend to a wall portion 50 l. This forms the set-up positionrestricting groove 50 h. Thread portions 50 k form the female helicoidgears 50 f and ends of these gears 50 f are eachspaced a predetermineddistance apart from the wall portion 50 l. In this way, the set-upposition restricting groove 50 h is defined by optical axial ends of therespective thread portions 50 k and the wall portion 50 l.

Incidentally, the position restricting projection guide portions 50 jhave a shorter thread height in a portion that extends into the set-upposition restricting groove 50 h. These shorter thread height portionsof the position restricting projection guide portions define malehelicoid inserting portions 50 m. The heights of (i) the positionrestricting projection guide portions 50 j (except at the male helicoidinserting portions. 50 m), (ii) the thread portions 50 k and (iii) thewall portion 50 l are approximately equal.

In the above-described construction, during the set-up movement ofcausing the lens barrel 5 b to move from the collapsed position L1 tothe photographing position, the set-up position restricting malehelicoid gears 51 a are displaced along the set-up position restrictingfemale helicoid gears 50 e according to the rotation of the cam frame51, and enter an end of the set-up position restricting groove 50 hdefined by the male helicoid insertion part 50 m. As the cam frame 51 isrotated further, the set-up position restricting male helicoid gears 51a are displaced to the wide angle end position L2 shown in FIG. 8, andmesh with the set-up position restricting groove 50 h defined by thewall portion 50 l and the ends of the thread portions 50 k. Namely, theend surfaces of each of the set-up position restricting male helicoidgears 51 a that are faced in the direction of the optical axis and theset-up position restricting groove 50 h mesh with each other.Accordingly, the position of the cam frame 51 in the direction of theoptical axis is defined. In this state, the meshed relationship betweenthe male helicoid of the cam frame 51 and the female helicoid of thestationary frame 50 is released.

Similarly, the male helicoid gears 51 b also enter the set-up positionrestricting groove 50 h, and mesh with the set-up position restrictinggroove 50 h with slight looseness as compared with the mesh between theset-up position restricting male helicoid gears 51 a and the set-upposition restricting groove 50 h. Accordingly, when only the set-upposition restricting gears 51 a mesh with the set-up positionrestricting groove 50 h, the position of the cam frame 51 in thedirection of the optical axis can be defined by only the set-up positionrestricting male helicoid gears 51 a, whereby smooth driving andaccurate positioning can be realized.

As described above, the set-up position restricting groove 50 hfunctions a second-frame position restricting groove for restricting theposition in the direction of the optical axis, of the cam frame 51 (thesecond frame). The set-up position restricting male helicoid gears 51 afunction as position restricting projections for restricting theposition in the direction of the optical axis, of the cam frame 51 (thesecond frame). The root portions which form the set-up positionrestricting female helicoid gears 50 e function as a positionrestricting projection guide groove for guiding the position restrictingprojections 51 a from the collapsed position L1 to the projectedposition.

In addition, since the male helicoid gears 51 b are set to be smaller inthread height than the set-up position restricting male helicoid gears51 a, and since the male helicoid inserting portions 50 m are formed inthe respective position restricting projection guide portions 50 j, whenthe cam frame 51 is rotating during zoom driving, the male helicoidgears 51 b and the position restricting projection guide portions 50 jdo not interfere with one another. That is, the male helicoid insertionportions 50 m can only restrict the “taller” male helicoid gears 51 a.Accordingly, the rotation angle of the cam frame 51 for zoom driving canbe set large, only limited by the male helicoid insertion portions 50 mand the “taller” male helicoid gears 51 a.

Furthermore, since the set-up position restricting male helicoid gears51 a are larger in thread height than the male helicoid gears 51 b, theamount of mesh between the set-up position restricting male helicoidgears 51 a and the set-up position restricting groove 50 h can be madelarge. Accordingly, even if external force is applied to the cam frame51, the position restriction of the cam frame 51 can be reliablymaitained. Thus, it is possible to obtain a lens barrel of highstrength.

Since the thread width of the set-up position restricting male helicoidgears 51 a is wider than the root width of the female helicoid gears 50f, it is possible to prevent the set-up position restricting malehelicoid gears 51 a from meshing with the female helicoid gears 50 fwhile the male helicoid gears 51 a move along the set-up positionrestricting groove 50 h.

On the other hand, in the case where the lens barrel 5 b is driven fromthe photographing position to the collapsed position, the set-upposition restricting male helicoid gears 51 a move in the set-upposition restricting groove 50 h toward the left as viewed in FIG. 8together with the rotation of the cam frame 51. Then, circumferentialend portions of the set-up position restricting male helicoid gears 51 acome to abut the position restricting projection guide portions 50 jwhich form the thread portions of the set-up position restricting femalehelicoid gears 50 e. When the cam frame 51 is rotated further in acollapsing direction from this state, the set-up position restrictingmale helicoid gears 51 a are guided by the position restrictingprojection guide portions 50 j and mesh with the set-up positionrestricting female helicoid gears 50 e. Simultaneously, the malehelicoid gears 51 b also mesh with the female helicoid gears 50 f. Inthis manner, the male helicoid of the cam frame 51 and the femalehelicoid of the stationary frame 50 mesh with each other, whereby thelens barrel 5 b is displaced to the collapsed position.

In this manner, the position restricting projection guide portions 50 jguide the thread portions of the set-up position restricting malehelicoid gears 51 a (which are position restricting projections) fromthe set-up position restricting groove 50 h to the root portions of theset-up position restricting female helicoid gears 50 e (which areposition restricting projection guide grooves).

A structure for securing the deformable mirror 40 to the stationaryframe 50, which moves in combination with the zooming operation of thelens barrel 5 b having the above-described construction, will bedescribed below in detail with reference to FIGS. 10 and 11.

FIGS. 10 and 11 are explanatory views of the construction and theoperation of the securing structure of the deformable mirror 40. FIG. 10is a, cross-sectional view of the portions of the lens barrel 5 b placedin the wide angle end state, and FIG. 11 is a cross-sectional view ofthe portions of the lens barrel 5 b placed in the collapsed state.

First, the securing structure of the deformable mirror 40 will bedescribed below.

As shown in FIG. 10, the deformable mirror 40 is supported to beinsertable into and retractable from the light path of the first tothird lens groups 30 to 32 by the link mechanism 60. Namely, thedeformable mirror 40 is secured so that when the lens barrel 5 b lies atthe collapsed position, the deformable mirror 40 can be retracted fromthe light path, and when the lens barrel 5 b lies at a photographingposition, the deformable mirror 40 can be inserted into the light path.

The deformable mirror 40 is turnably supported in the mirror holdingpart 50 a of the stationary frame 50 in such a way that the mirrorturning shaft 40 h inserted through the bearing parts 40 f is pivotallysupported in the mirror holding part 50 a of the stationary frame 50. Inthis case, the urging spring 40 i is engaged with the mirror holdingpart 50 a of the stationary frame 50 and the bearing parts 40 f, andthis urging spring 40 i normally urges the mirror holding frame 40 ctoward the interior of the stationary frame 50 (in the direction of theoptical axis).

The link mechanism 60 includes mirror link members 61 for movablysupporting the mirror holding frame 40 c. Each of these mirror linkmembers 61 is turnably supported at its proximal end by a link shaft 61a, and this link shaft 61 a is pivotally supported in the mirror holdingpart 50 a of the stationary frame 50, thereby enabling the mirror linkmembers 61 to turn about the link shaft 61 a.

A slot-shaped guide hole 60 b is formed to extend from the vicinity ofthe center of each of the mirror link members 61 toward the vicinity ofone end of the same. Holding frame pins 45 which are respectively fixedto the opposite sides of the mirror holding frame 40 c at positionssomewhat close to the thin film 40 a from the center of the mirrorholding frame 40 c are fitted movably in the respective guide holes 60b. Namely, since the holding frame pins 45 are guided by theirengagement with the guide holes 60 b, the mirror holding frame 40 c canbe turned according to the turn of the mirror link members 61. Aflexible printed circuit board 44 led from the deformable mirror 40 isextended to the back side of the mirror holding frame 40 c through theflexible printed circuit board inserting hole 40 e of the mirror holdingframe 40 c, and after having been led to run on the back side of themirror holding frame 40 c, the flexible printed circuit board 44 is ledto be wound around the object side of the mirror shaft 40 h from aflexible printed circuit board inserting hole 40 j formed in thevicinity of the mirror shaft 40 h. After that, the proximal end of theflexible printed circuit board 44 is electrically connected to anelectronic control circuit including the mirror driving circuit 26 andthe CPU 11 via a flexible printed circuit board inserting hole 40 kformed in the top portion of the bearing parts 40 f and a flexibleprinted circuit board inserting hole 50 i of the stationary frame 50.Namely, the above-described wiring pattern is simple and preferredbecause it does not influence the turning of the deformable mirror 40.

Incidentally, the image pickup device 13 is fixed to the CCD holdingpart 50 c of the stationary frame 50, and an optical low-pass filter 62and an infrared cut filter 63 are disposed on the image pickup device 13in a stacked manner. The optical low-pass filter 62 and the infrared cutfilter 63, which are disposed at the front stage of the image pickupdevice 13, eliminates unnecessary reflected light from the deformablemirror 40 and helps to improve image-forming performance.

In this camera 1, the turning of the deformable mirror 40 having theabove-described construction is mechanically driven in combination withthe zooming operation of the lens barrel 5 b. Namely, as shown in FIG.10, the pressing part 52 c of the zooming frame 52 that is disposed atthe rear end of the lens barrel 5 b is disposed to be able to come intocontact with a part of the reflecting surface side of the mirror holdingframe 40 c of the deformable mirror 40, and during the zooming operationof the lens barrel 5 b from the wide angle end position to the telephotoend position, the pressing part 52 c is placed in a non-contact state orin such a contact state that the pressing part 52 c does not influencethe turning of the mirror holding frame 40 c.

During this time, since the mirror holding frame 40 c is urged towardthe interior of the stationary frame 50 (towards and intersecting theoptical axis) by the urging spring 40 i, the mirror holding frame 40 cis pressed down by this urging force, and the holding frame pins 45 ofthe mirror holding frame 40 c are respectively brought into contact withthe bottoms of the guide holes 60 b of the mirror link members 61 andare held in this state. Accordingly, the deformable mirror 40 ispositioned in the light path defined by the first to third lens groups30 to 32, whereby light coming through the first to third lens groups 30to 32 can be reflected by the thin film 40 a of the deformable mirror 40onto the image pickup device 13.

On the other hand, when the lens barrel 5 b is shifted from the wideangle end position to the collapsed position, although the mirrorholding frame 40 c is urged toward the interior of the stationary frame50 (in the direction of the optical axis) by the urging spring 40 i, thepressing part 52 c of the zooming frame 52 disposed at the rear end ofthe lens barrel 5 b presses the mirror holding frame 40 c upward whilesmoothly sliding in contact with the reflecting surface side of themirror holding frame 40 c of the deformable mirror 40 in accordance withthe collapsing of the lens barrel 5 b into the stationary frame 50. Inaccordance with this movement, the holding frame pins 45 of the mirrorholding frame 40 c turn the mirror link members 61 upward while beingguided by the guide holes 60 b of the mirror link members 61.

After that, when the lens barrel 5 b completely reaches the collapsedposition, the mirror holding frame 40 c is completely pressed up, and atthe same time, the holding frame pins 45 turn the mirror link members 61upward while preferably being held in contact with the tops of the guideholes 60 b (the proximal ends of the guide holes 60 b closer to the linkshaft 61 a), whereby the mirror holding frame 40 c is positioned at aphotography-disabled retracted position. Namely, when the lens barrel 5b is collapsed, the optical function of the deformable mirror 40 is notneeded, so that the deformable mirror 40 may be retracted from the lightpath of the first to third lens groups 30 to 32, e.g., completelyaccommodated in the mirror holding part 50 a. In this case, the mirrorholding frame 40 c is normally urged in the direction of the opticalaxis by the urging spring 40 i, to be held against the pressing parts52C. Consequently, even if the camera 1 is shaken while being carried,the deformable mirror 40 does not shake, and can be reliably held in anaccommodated state.

An example of the photographing operation control of the CPU 11incorporated in the camera 1 will be described below with reference toFIG. 12.

FIG. 12 is a flowchart showing an example of the photographing operationcontrol of the CPU 11 incorporated in the camera 1. The AF systemadopted in this example is, for example, a known hill-climbing schemeauto-focus system or contrast detection type auto-focus system. Theshape of the thin film 40 a of the deformable mirror 40 may also becontrolled on the basis of the result of distance detection using otherdistance detection systems such as an active auto-focus system and aphase difference detection (passive) type auto-focus system.

It is assumed now that the power source switch (not shown) of the camera1 shown in FIG. 1 is turned on and the lens barrel 5 b is zoomed by themanipulation of the lever ZL so that a picture can be taken at thedesired angle. It is also assumed that the deformable mirror 40 ispositioned as shown in FIG. 10 by the link mechanism 60 as the result ofthe zooming of the lens barrel 5 b.

At this time, the CPU 11 determines in the Step S1 whether the firstrelease detecting switch 8 a has been turned on by the depression of therelease button 8, and stands by until the first release detecting switch8 a is turned on. After that, if the CPU 11 determines in the Step S1that the first release detecting switch 8 a has been turned on by thedepression of the release button 8, the CPU 11 transfers the process tothe next step S2.

If the CPU 11 determines that the first release detecting switch 8 a hasbeen turned on, the CPU 11 performs contrast peak detecting process inthe Step S2. In this contrast peak detecting process, since a picked-upimage signal supplied from the image pickup device 13 is subjected tosignal processing by the image signal processing circuit 14 and theobtained contrast data is supplied to the CPU 11, the CPU 11 performscontrol on the mirror driving circuit 26 (refer to FIG. 3) to vary theshape of the thin film 40 a of the deformable mirror 40 in astep-by-step manner, thereby detecting the contrast of the picked-upimage signal. On the basis of the detection result, the CPU 11 performscontrol on the mirror driving circuit 26 to vary the shape of the thinfilm 40 a of the deformable mirror 40 so that the contrast is maximized.Thus, the camera 1 is brought into an in-focus state.

Incidentally, the camera 1 may also be constructed to have a storagepart which previously stores control information for comparing contrastdata and the state of deformation of the thin film 40 a of thedeformable mirror 40. The CPU 11 uses the control information stored inthe storage part to control the shape of the thin film 40 a of thedeformable mirror 40 so that contrast is maximized.

When the in-focus state is reached in this manner, the CPU 11 performsphotometric measurement processing in the next step S3. For example, theCPU 11 performs photometric measurement using picked-up image datasupplied from the image signal processing circuit 14. Incidentally, thephotometric measurement processing may be executed with a knownalgorithm.

Then, the CPU 11 transfers the process to Step S4, and determines in theStep S4 whether the second release detecting switch 8 b has been turnedon by the depression of the release button 8. If the CPU 11 determinesthat the second release detecting switch 8 b has been turned on, the CPU11 transfers the process to the next step S6. If the CPU 11 determinesthat the second release detecting switch 8 b is off, the CPU 11determines in the next step S5 whether the first release detectingswitch 8 a has been turned on. If the CPU 11 determines that the firstrelease detecting switch 8 a has been turned on, the CPU 11 returns theprocess to Step S4 and stands by until the second release detectingswitch 8 b is turned on. If the CPU 11 determines in the Step S5 thatthe first release detecting switch 8 a is off, the CPU 11 brings theprocess to an end.

When the second release detecting switch 8 b is turned on, the CPU 11performs control in the image pickup device 13 to execute image pickupprocess using the image pickup device 13. In this manner, photography iscompleted, and the CPU 11 brings the camera 1 into a photography-enabledstate.

Accordingly, in this example, the camera 1 is provided with thedeformable mirror 40 which can be inserted into and retracted from thelight path of the picture taking optical system 5 a by means of the lensbarrel 5 b which linearly moves back and forth in the directions of theoptical axis, whereby the picture taking optical system having a smallsize and a simple construction can be formed in the camera 1. Inaddition, the fact that the image pickup device 13, is disposed on thestationary frame 50 of the lens barrel 5 b greatly contributes to areduction in the size of the camera 1.

In this manner, the deformable mirror 40 is arranged at the rear stageof the position of the aperture diaphragm 18 of the picture takingoptical system 5 a, and the first to third lens groups 30 to 32 drivenback and forth during zooming are arranged in the lens barrel 5 b whichcan be projected from and retracted into the camera body 2. Accordingly,even if an optical system having a particularly high zooming ratio isused, the size of the camera body 2 need not be extremely increased.When the lens barrel 5 b is to be collapsed, the deformable mirror 40 isretracted, and the lens barrel 5 b is accommodated into a spaceremaining after the retraction of the deformable mirror 40. Accordingly,the size of the camera 1 with the lens barrel 5 b accommodated can bereduced. In this example in particular, since the deformable mirror 40is disposed on the rearmost side of the picture taking optical system 5a (a position closest to a picture taking medium in the picture takingoptical system), no other optical lens elements need be disposed in thecamera body 2, whereby it is possible to achieve a further reduction inthe size of the camera 1.

In addition, since the optical characteristics of the mirror can bevaried by electrical control, a lens driving mechanism can be simplifiedor omitted, whereby it is possible to realize not only a reduction inthe camera size but also high speed response and silent operation.

In addition, since the camera 1 is constructed so that the turningoperation of the deformable mirror 40 is executed by the link mechanism60 and the lens barrel 5 b which linearly moves back and forth in thedirection of the optical axis, it is possible to achieve the advantagesof suppressed driving noise and enabling high speed response.

Furthermore, driving and control for deformation of the thin film 40 aof the deformable mirror 40 can be achieved with an extremely smallelectric current value, whereby the consumption of the battery of thecamera 1 can be minimized, thereby saving energy.

In addition, in this example, when the deformable mirror 40 is to beretracted from the light path, the mirror holding frame 40 c is pressedby the frame member of the lens barrel 5 b that is driven linearly inthe direction of the optical axis, so that the frame member comes intocontact with the mirror holding frame 40 c in the hatched areas shown inFIG. 6. Accordingly, since the sliding locus of the pressing part 52 cformed on the zooming frame 52, which is a driving frame, becomeslinear, a space in which to dispose the deformable mirror 40 can beprovided in the center of the mirror holding frame 40 c, so that thesize of the camera can be reduced.

Furthermore, since the lens groups and the deformable mirror which areconstituent elements of the picture taking optical system are directlyor indirectly held by the stationary frame which is formed as a singleframe member, the positional relationship between the lens groups andthe deformable mirror can be determined with high precision, and theoptical performance of the picture taking optical system is notimpaired. In addition, since the image pickup device is also held by thestationary frame, the lens groups, the deformable mirror and the imagepickup device can be positioned with higher precision.

Incidentally, in this example, the deformable mirror is used forfocusing, but the deformable mirror is not limited to such a use. Forexample, the deformable mirror may be used for zooming the picturetaking optical system, or may also be used for various corrections suchas correction of aberration accompanying zooming operation. Accordingly,the invention can of course greatly contribute to reducing the size ofthe camera 1, and can also improve the performance of the camera 1.

In addition, according to this example, the position of the barrel framein the direction of the optical axis is defined with respect to theprojected; position by using the helicoids to be used for the movementof the lens barrel 5 b from the collapsed position to thephotography-enabled projected position. Accordingly, set-up and turn-offdriving between the collapsed position and the projected position andzoom-in and zoom-out driving between the wide angle end position and thetelephoto end position are realized without using any complicatedmechanism. Namely, the switching of power between the set-up movementand the zooming movement is not at all needed.

In addition, independent driving means are respectively used for set-upmovement and zooming movement, whereby the amount of set-up driving andthe amount of zooming driving can be set large.

This invention is not limited to the above described example and a lotof variation are possible within the scope of this invention. Suchvariations are not to be regarded as a departure from the spirit andscope of the invention. Rather, the scope of the invention shall bedefined as set forth in the following claims and their legalequivalents. All such modifications as would be obvious to one skilledin the art are intended to be included within the scope of the followingclaims.

1-9. (canceled)
 10. A lens barrel comprising: an optical systemincluding at least one lens and a reflecting member for reflecting lightpassing through the at least one lens; an image pickup element providedat a position where the image pickup element can receive light reflectedfrom the reflecting member; and a frame which supports the reflectingmember and the image pickup element, the reflecting member beingsupported on the frame in such a manner as to be insertable into andretractable from a light path of the optical system.
 11. The lens barrelrecited in claim 10, wherein the reflecting member has an optical power.12. The lens barrel recited in claim 10, wherein the reflecting memberhas a variable optical power.
 13. The lens barrel recited in claim 10,wherein the reflecting member has a reflecting surface whose shape isvariable, and has optical power which varies by varying the shape of thereflecting surface.
 14. The lens barrel recited in claim 10, the opticalsystem further comprising an aperture diaphragm, wherein the reflectingmember is disposed on the light path between the image pickup elementand the aperture diaphragm.
 15. The lens barrel recited in claim 14,wherein the reflecting member is disposed on a rearmost position of theoptical system. 16-36. (canceled)
 37. An image capture apparatuscomprising: a lens system including a plurality of lens groups adaptedto move along an optical axis which defines at least a part of an imageacquiring optical path; and a mirror, wherein the lens system has afirst state and a second state, wherein, when the lens system is in thefirst state, the mirror is positioned in the image acquiring opticalpath in a defined space, and wherein, when the lens system is in thesecond state, each of at least two of the plurality of lens groupsoccupy at least a part of the defined space.
 38. An image captureapparatus having an image acquiring optical path, comprising: a mirror;and a mirror retracting part, wherein the mirror has a first state inwhich it is positioned in the image acquiring optical path, and a secondstate in which it is positioned outside the image acquiring opticalpath, and wherein the mirror and mirror retracting part aresubstantially parallel with respect to each other when the mirror is inthe second state.
 39. The apparatus of claim 38 further comprising: alens system having at least two lens barrel segments, wherein when themirror is in the second state, both the mirror and the retracting partare accommodated between two of the at least two lens barrel segments.40. The apparatus of claim 39, wherein one of the at least two lensbarrel segments is a stationary frame which is fixed with respect to abody of the apparatus and another of the at least two lens barrelsegments is a movable frame which is movable between a positionsubstantially accommodated in the stationary frame and a positionprotruding from the stationary frame.
 41. (canceled)